What does StackOptic analyze?

StackOptic runs 18 analysis modules on any public website from a single URL. It detects 7,000+ technologies (CMS, frameworks, analytics, payments, CDN, hosting), evaluates SSL certificates and HTTP security headers with grades from A+ to F, measures Core Web Vitals (LCP, CLS, TBT, FCP), audits SEO meta tags and structured data, checks email security (SPF, DKIM, DMARC), analyzes AI & LLM readiness including bot access and llms.txt validation, extracts color palettes and typography, estimates carbon footprint, and generates permanent shareable reports.

Does it work on sites behind Cloudflare or bot protection?

Yes. StackOptic uses a real browser engine that loads pages exactly like a human visitor — executing JavaScript, rendering CSS, and handling redirects. This allows it to bypass Cloudflare, LiteSpeed, Sucuri, and other bot protection systems where traditional crawlers and HTTP-only tools fail.

What do I get on the free plan?

The free plan includes 5 analyses per day with access to all 18 modules, full scores, technology detection, and security grades. Every report is permanently accessible via a unique shareable URL — no login required to view. No credit card needed. AI-powered insights, re-analysis, PDF/JSON export, and comparison features are available on Pro ($24/mo) and Agency ($99/mo) plans.

What is AI & LLM readiness analysis?

This module evaluates how visible and citable your website is to AI search engines like ChatGPT, Perplexity, Google AI Overviews, and Claude. It audits access permissions for 8 major AI bots, validates llms.txt and llms-full.txt files, scores citation-ready content structure, and analyzes structured data (JSON-LD) for GEO readiness — helping you rank in the next generation of search.

How long does an analysis take?

Most analyses complete in under 10 seconds. StackOptic runs all 18 modules in parallel using a real browser session, so you get technology detection, security audit, performance metrics, SEO analysis, and AI readiness scoring simultaneously.

How accurate are the results?

Detection is based on real browser execution — DOM inspection, JavaScript runtime analysis, HTTP headers, and DNS records. With 7,000+ technology signatures and Lighthouse-calibrated performance scoring, StackOptic achieves high accuracy for mainstream technologies.

What security checks are performed?

The security module evaluates SSL/TLS certificates, 12+ HTTP security headers (HSTS, CSP, X-Frame-Options, Permissions-Policy, Referrer-Policy), HTTPS enforcement, and email authentication (SPF, DKIM, DMARC). Each site receives a letter grade from A+ to F with specific remediation steps.

Do you store the websites I analyze?

StackOptic only stores publicly available information that any visitor to a website would see — HTML content, HTTP headers, DNS records, and screenshots. We do not access private data, log in to websites, or perform any intrusive testing.

Back to Search

thredup.com

https://thredup.com· First analyzed 17 Feb 2026· Updated 17 Feb 2026

Export

thredup.com

Sponsored

Hosting Provider

Cloudflare

cloudflare.com

IP Address

104.18.34.29

Server Location

🇨🇦 Toronto, Canada

ASN

AS13335

Organization

Cloudflare, Inc.

Server

Cloudflare

CDN

Cloudflare

WAF

Cloudflare

Nameservers

matt.ns.cloudflare.com.rose.ns.cloudflare.com.

Performance

Page Speed

850 KB

172 requests

Image Optimization

Lazy LoadResponsive

0–49

50–89

90–100

Architecture Stack

Monolithic

⚙️ SSR

Frontend

Styling

Tailwind CSS

Infrastructure

Hosting

Cloudflare

CDN

Cloudflare

Progressive Web App

PWA ReadyWeb ManifestService WorkerApple Touch IconTheme Color

Technology Stack

9 Technologies Detected

Analytics

Google Analytics

Google Analytics 4

Facebook Pixel LogRocket

Advertising

TikTok Pixel Microsoft Advertising

CSS Frameworks

Tailwind CSS

Tag Managers

Google Tag Manager

CDN

Cloudflare

SEO Analysis

A+94/100

thredup.comthredup.com

ThredUp | An Online Consignment & Thrift Store

ThredUp is an online consignment and thrift store where you can buy and sell high-quality secondhand clothes. Find your favorite brands at up to 90% off.

Title Length46 chars

Recommended: 50-60 chars

Description Length153 chars

Recommended: 120-160 chars

Issues (0)

1 issues found

Upgrade to view details

Sponsored

Security Score

61%Fair

Interactive

HTTPS

WAF

89d

Certificate Details

Type

Domain Validated (DV)

Certificate Authority

Google Trust Services

Key Algorithm

ECDSA (secp256r1) (256 bit)

Signature

ECDSA with SHA-256

TLS Version

TLSv1.3

HTTP Protocol

HTTP/2+H3

Valid From

16.02.2026

Valid Until

18.05.2026

OCSP Stapling

Enabled

Subject Alternative Names (2)

thredup.com*.thredup.com

SHA-256 Fingerprint

9C:21:B1:A5:74:98:83:72:B3:BB:76:E6:6A:C9:F3:0A:AA:14:4B:E6...

Top Recommendations

Security recommendation preview

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HTTP Headers

Developer Console

date

Tue, 17 Feb 2026 09:01:29 GMT

content-type

text/html; charset=utf-8

content-encoding

⚡ Brotli(br)

cf-ray🇩🇪 Frankfurt

9cf419b20a029b2d-FRA

cf-cache-status

DYNAMIC

cache-control

🔴 No Cache(no-store)

Good Warning Issue

Email Infrastructure

Google Workspace

Score

100

SPF

DKIM

DMARC

DMARC Policy

Reject (Strictest)

MX Records (5)

alt2.aspmx.l.google.com

aspmx.l.google.com

aspmx3.googlemail.com

aspmx2.googlemail.com

+1 more

Domain Information

thredup.com

Domain Age

17y 3m

Created

15.11.2008

Expires

16.10.2026

Last Updated

04.10.2022

Registrar

GoDaddy.com, LLC

DNSSEC

Not Enabled

Privacy & Compliance

OneTrust

Cookie Consent Banner

OneTrust

GDPR Indicators

Cookie consent banner detected

CMP: OneTrust

Data Protection Officer mentioned

Typography & Readability

Season Serif + sans-serif

59/100

Readability

/30

32/40

14px · LH 1.60

Hierarchy

/20

11/25

1x ratio

WCAG

/25

15/15

Contrast: undefined

Performance

/25

13/20

2 fonts

Heading Font

Season Serif

Serif14px

Body Font

sans-serif

Sans14px

Contrast Ratio

Reading Comfort

~87 CPL

Needs attention

14px

48px

12px

20px

14px

Golden Ratio

Scale

⚠️ Small text: 14px may be hard to read on mobile. Consider 16px+.

✅ Optimal line spacing: 1.60 ratio ensures comfortable reading.

⚠️ Weak hierarchy: Headlines should be at least 2x body size for clear visual structure.

✅ Good performance: Using 2 font families keeps load times fast.

✅ Smart font loading: Using font-display: swap prevents invisible text during load.

✅ Protected text on images: Using gradient for readability.

Buy on MyFonts

Business & Marketing Stack

6 Tools Detected

Enterprise

Behavior Analytics

Google Tag ManagerFree

Google AnalyticsFree

User behavior and product analytics

Advertising

Facebook PixelMid-Market

TikTok PixelMid-Market

Microsoft AdsEnterprise

Ad platforms and retargeting pixels

Affiliate & Partnerships

AWINMid-Market

Affiliate networks and partner tracking

Sponsored

Scripts & Styles

30 Resources

Scripts

Styles

Async

Defer

Top Script Sources

local(8)googletagmanager.com(4)connect.facebook.net(2)cdn.pbbl.co(1)cdn.sprig.com(1)

Website Identity

Facebook X (Twitter)Instagram Pinterest

Sponsored

Last analyzed: 17 Feb 2026 at 09:01

Historical Analysis & Change Tracking